The banks targeted in this attack where, U.S. Bancorp, JPMorgan Chase,Bank of America, PNC, and SunTrust. Many Users started reporting problems accessing banking websites Tuesday evening, and some sites were still intermittently inaccessible on Wednesday afternoon.

“PNC and other banks have experienced an unusual volume of internet traffic. As a result, some customers may experience slowness or difficulty when logging into online and mobile banking. We are working to resolve this issue as quickly as possible. Please continue to follow our page for additional updates. We apologize for the inconvenience and appreciate your patience,” PNC posted on its Facebook page Tuesday evening.

They went on in the Pastebin post to explain,

Now, we acclaim that the second phase of the Ababil operation is in ahead and from this week according to the announced plan, will be performed. In new phase, the wideness and the number of attacks will increase explicitly; and offenders and subsequently their governmental supporters will not be able to imagine and forecast the widespread and greatness of these attacks.

An analysis by Radware found that the group was using compromised servers to launch DDoS attacks. Since servers in data centers generally have bigger bandwidth, the attacks were large enough to overwhelm network defenses.

The fact that some of the banks took to social media to warn customers about potential attacks this time around was “a sure sign that these hacktivists are beginning to hit a nerve,” Stephen Gates of technology evangelist at Corero Network Security said.